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F. Matsumoto, Y. Nakao, A. Wakayama, K. Ohmure, Y. Shimomura; A Study of the Crowding Phenomenon using the Landolt Ring Crowded Card in Cases with Microtropic Amblyopia . Invest. Ophthalmol. Vis. Sci. 2003;44(13):4842.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:To study the crowding phenomenon using the Landolt Ring Crowded Card with cases exhibiting microtropic amblyopia. We reported the cases of crowding phenomenon in children exhibiting anisometropic amblyopia were more obvious than in normal children using the Landolt Ring Crowded Card. Methods:The sublects were between five and ten years old. The cases consisted of seventeen subjects being treated for microtripic amblyopia. The corrected vision of an amblyopic eye was between 5/20 and 24/20. The Landolt Ring Crowded Card consisted of Landolt rings with a visual angle between 5 and 13 minutes. The central Landolt ring was placed in the center of an octagonal shaped card and six Landolt rings were placed around the central Landolt ring. Distances from the central to outer Landolt rings were 1,2.5,5,10,15,20,25 and 30 minutes,respectively. Results:The sublects' sound eye was able to accurately identify the visual angle of crowding phenomenon from 1 minute to 10 minutes,while the amblyopic eye showed from between 5 to 30 minutes using the Landolt Ring Crowded Card in cases with microtropic amblyopia. There were no differences between the amblyopic and sound eyes in only three cases. In 14 out of 17 cases,the results of the crowding phenomenon was more obvious in the amblyopic eyes. Five cases showed the crowding phenomenon of 25 minutes or over,and remained at parafoveal fixation despite amblyopic treatment. Conclusions: The crowding phenomenon of the amblyopic eye was more obvious in microtropic amblyopia cases than in the anisometropic amblyopia ones.
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